1-Alkoxy-1-trimethylsilyloxycyclopropanes are known to be an important raw material used in synthesis of N-cyclopro-pylamines which are raw materials in synthesis of medicines and agricultural chemicals (Chem. Comm., 1987, p. 897; Tetrahedron Lett., 1995, p. 7399). Since showing a very characteristic reactivity of homoenolate anion equivalent in a carbon-carbon bond-forming reaction, they are also known to become an important intermediate in synthesis of perfumes, etc. (J. Amer. Chem. Soc., Vol. 108, p. 3745, 1986).
As to the process for synthesis of 1-alkoxy-1-trimethylsilyloxycyclopropane, a process is well known which comprises reacting 3-chloropropionic acid ester with sodium sand in the presence of trimethylchlorosilane in an ether solvent (Org. Synthesis, Vol. 63, p. 147, 1984).
The process, however, has a problem of complicated operation such as the following. That is, metallic sodium is heat-melted in toluene or xylene and stirred, followed by cooling to form sodium sand; only the supernatant portion of the solvent is taken out; the residual metallic sodium is washed a plurality of times to change the solvent to ether. Further, the above process can be conducted in a laboratory flask but has been difficult to carry out on an industrial scale for the following reasons, for example. In this procedure, metallic sodium catches fire easily when water comes in; and the ether used as a reaction solvent has a low flash point and is difficult to recycle, and when the ether is used in a large amount, it easily forms a peroxide which is explosive.
Meanwhile, it is described in Synlett, p. 89, 1990 that the above reaction, when an ultrasonic is applied to the reaction system, proceeds without making metallic sodium as sand-like one by heat-melting or the like. However, use of ultrasonic in industrial production requires a special apparatus, which is disadvantageous in cost and not practically suitable for industrial production.